Slip a shirt, slop a sunscreen and slap a hat

For many years, dermatologists have advised their patients to avoid or, at the very least, severely limit exposure to the sun since ultraviolet (UV) radiation is the primary cause of skin cancer, external skin aging, wrinkles, and blotchy pigmentation on the skin.

Of all the skin care advice that is doled out to patients, Proper protection from the sun will make a great difference in the patient's future appearance. Patients should be advised that if they do not avoid the sun and practice protective measures, they are wasting their money on cosmetic products and procedures.

Obviously, the daily use of sunscreen is an important adjunct to skin protective behavior. However, because no sunscreen can effectively block all parts of the UV spectrum, sun avoidance, protective clothing and hats, and window shields can all be utilized to lessen acute and cumulative sun exposure damage.

About the UV Rays of the Sun

UVB is blocked by glass and the amount of UVB that reaches the earth’s surface varies by the time of day, with maximal rays reaching the earth from 10 AM to 4 PM. UVA radiation can pass through glass. UVA penetrates deeper into the skin, contributing to cutaneous wrinkling and aging. UVA damages deeper layers of the skin.

Unfortunately, the sun protection factor (SPF) primarily assesses the protective effects against UVB light, leaving UVA out of the picture.

What is SPF?

SPF is defined technically as the level of sun exposure needed to produce a minimal erythema divided by the amount of energy required to produce the same erythema on unprotected skin.

Three Types of Tests to Determine Sunscreen Efficiency

Sun Protection Factor (SPF)

To Protect skin against UVB (and some UVA) wavelengths

UVA Protection Factor (UVAPF)

To protect skin from developing persistent pigment darkening (PPD) induced by UVA exposure

Broad-Spectrum Protection And Photostability

To provide broad-spectrum protection against UVB and UVA; to prevent rapid degradation from UV exposure


Water Resistant

A sunscreen is considered water resistant if the SPF level is determined effective after 40 minutes of water immersion.

Physical Sunscreen

Chemical and physical Barrier sunscreens, known more commonly as physical sunscreens, scatter or reflect UV radiation and are rarely associated with allergic reactions. These sunscreens block the widest range of light including UV, visible, and infrared spectra, and are recommended for use especially when intense sun exposure, such as at the beach or at high altitudes, is expected. Sensitive skins are more likely to tolerate this type of sunscreens. Titanium dioxide (TiO2), magnesium oxide, iron oxide, and zinc oxide (ZnO) are the primary ingredients in physical sunscreens. There have been no reports of contact allergy to these components.

Chemical Sunscreen

Chemical sunscreens are usually combined with physical sunscreens or with each other to form high-SPF products that can be used during times of significant sun exposure. Chemical sunscreens absorb UV radiation.

Chemical sunscreens are composed of synthetically prepared organic chemicals that can be broadly labeled as UVB or UVA-absorbing substances. Many chemical sunscreens have been reported to cause allergic or photo allergic reactions in susceptible patients.

Stability of Sunscreens

One of the main requirements in the developments of a sunscreen is that the product be photostable, or maintains its intended protection for a limited time before inevitable breakdown caused by UV exposure.

Vitamin D and Sunscreen

Vitamin D is important for the prevention of many types of cancers. Best method for obtaining a healthy and proper dose of vitamin D is through the sun. Supplements, pills, and fortified milk do not contain the proper recommended dose of daily vitamin D. in addition, sunscreen block most UVB light. It is UVB that promotes the synthesis of vitamin D. researchers recommended a few minutes in the sun without sunscreen but advise against sun exposure for any significant elapsed amount of time.

Intermittent use of Sunscreens

Many sunscreens users may have the misconception that intermittent use of a high-SPF product is as effective as daily use of a lower-SPF product. One study demonstrated that sunscreens must be applied properly, regularly, and in appropriate amounts to be optimally effective in preventing UV-induced skin damage. The finding suggests that missing an application of sunscreens, even potent one, can have negative consequences for the skin.

Protective effects of Makeup and Other Skin Care Products

Sunscreens ingredients are now commonly found in many makeup foundations. Most facial foundations provide some sun protection as a result of ingredients such as Titanium di oxide and the pigments used to color the product. Consequently, chemical sunscreens are more often added to impart protection.

Within the last few years, manufactures have produced hair care products, notably shampoos and conditioners that contain sunscreens ingredients. Such ingredients are probably rinsed away and rendered ineffective because many sunscreen ingredients are water soluble and many of the hair care products are intended to be rinsed out. Although there are no data establishing their effectiveness, leave-in hair care products are more likely to provide some protection to the hair shaft. The best recommendation is to wear a hat to prevent sun damage to the hair.


There are numerous sunscreens choices on the market. It is important to help patients find the sunscreen that is most suitable for their needs. It is even more important to emphasize that the daily use of sunscreen is not the first-line defense against the sun and that sunscreen use does not protect a person from photodamage or give one license to stay out longer because of coating of sunscreen. The daily use of sunscreens is an important ingredient, though, in the continuing efforts to keep the skin looking young and healthy.